Definition of Computer

Computer: The word computer is taken from the Latin word “compute” which means “calculate”. According to the Oxford English Dictionary, the word "computer" was first used to describe a mechanical calculating device in 1897.

A computer is an electronic and programmable device used to solve a lot of problems in our daily life. It is used to store and process data to make decision.

Historical Evolution of Computers

Father of modern computers - Charles Babbage (British mathematician)Invented computers (mechanical): Analytical Engine, Difference Engine.

Generation of Computer: The gradual development of present computers over past computers are divided into different time periods. Each time period is considered as a generation of computer.

The parameters which are used to measure the development of present computers over past computers are:

Space: Space must be minimized.Speed: Speed must be maximized.Capacity: Capacity must be maximized.Cost: Cost must be minimized.

Generation of Computer

Generation Period TechnologyFirst Generation Computers 1942–1955 Vacuum Tube

Second Generation Computers 1956–1965 Discrete Transistors

Third Generation Computers 1966–1975 Integrated Circuits (ICs)-SSI

Fourth Generation Computers 1976–1985 MSI , LSI

Fifth Generation Computers 1986–onwoards VLSI, VVLSI (ULSI)

IC Chip(1”x0.5”) Full meaning No. of Discrete Transistors

(Approximately)SSI Small Scale Integration 1000

MSI Medium Scale Integration 10,000

LSI Large Scale Integration 100000

VLSI Very Large Scale Integration 10,00000

VVLSI Very Very Large Scale Integration 10000000

ULSI Ultra Large Scale Integration 10000000

Different Generation of Computers and Their Used Technologies